Fixing compilation errors related to OpenGL

[du-xinyi]

Fixes #3596

Pull Request Readiness Checklist

See details at https://github.com/opencv/opencv/wiki/How_to_contribute#making-a-good-pull-request

• I agree to contribute to the project under Apache 2 License.
• To the best of my knowledge, the proposed patch is not based on a code under GPL or another license that is incompatible with OpenCV
• The PR is proposed to the proper branch
• There is a reference to the original bug report and related work
• There is accuracy test, performance test and test data in opencv_extra repository, if applicable
  Patch to opencv_extra has the same branch name.
• The feature is well documented and sample code can be built with the project CMake

[asmorkalov]

@du-xinyi Please share your issue description. I just build OpenCV with contrib and enabled OpenGL. It works just fine and passed tests on Ubuntu.

[du-xinyi]

@du-xinyi请分享您的问题描述。我刚刚使用 contrib 构建了 OpenCV 并启用了 OpenGL。它运行良好并通过了 Ubuntu 上的测试。

I encountered an issue related to GL when compiling on Ubuntu 20.04. The detailed error message is available at this link. The missing function is located in gl/glew.h.

[asmorkalov]

I made experiments with Ubuntu 18.04, 20.04 and 24.04. Only Ubuntu 24.04 provides QT6 package (6.4.2). All the combinations were built just fine and passed tests. Looks like your QT build is not complete.

[du-xinyi]

我使用 Ubuntu 18.04、20.04 和 24.04 进行了实验。只有 Ubuntu 24.04 提供了 QT6 包 (6.4.2)。所有组合都构建得很好，并通过了测试。看来您的 QT 构建不完整。

I built qt using qt's online installer. glGenRenderbuffersEXT These functions are not currently in '/usr/include/GL/gl.h', but the missing functions can be found in '/usr/include/GL/glew.h'